The "This Is the End" star, 31, who serves as an Alzheimer's Assn. celebrity champion, addressed a Senate committee about the neurodegenerative disorder and opened up about the plight of his mother-in-law, Adele, his authenticity punctuated with self-deprecating humor during a hearing about the rising cost of Alzheimer's.

"I came here today for a few reasons. One, I'm a huge 'House of Cards' fan. Just marathoned the whole thing, had to be here," quipped Rogen, who started the Alzheimer's organization Hilarity for Charity.

"Two, is to say, people need more help. I've personally seen the massive amount of financial strain this disease causes and if the American people ever decide to reject genitalia-driven comedy, I will no longer be able to afford it. ... I can't begin to imagine how people with more limited incomes are dealing with this. ... The third reason I'm here, simply, is to show people that they are not alone, so few people share their personal stories."

Rogen, who explained how he was personally affected by the disease, said that it's the most costly condition in the United States, trumping heart disease. He said deaths from Alzheimer's have increased almost 70% in the last 15 years, adding that more than 5 million Americans have it, with as many as 16 million Americans projected to have it within the next 35 years.

He said that when he met his wife Lauren Miller's mother, Adele, she was 54 and was diagnosed with early onset Alzheimer's shortly after.

"I thought it was something only really, really old people got and I thought the way the disease primarily showed itself was in the form of forgotten keys, wearing mismatched shoes and being asked the same question over and over," he admitted.

That period lasted a few years for Adele, he said, before he "saw the real ugly truth of the disease."

"After forgetting who she and her loved ones were," Rogen continued, she "forgot how to speak, feed herself, dress herself and go to the bathroom herself, all by the age of 60."

His and Miller's personal plight with Alzheimer's opened his eyes to the "shame and stigma" around the disease and prompted them to "actually try and do something to change the situation."

Hilarity for Charity, a fund with the Alzheimer's Assn., is meant to raise money to help families and support Alzheimer's research in pursuit of a cure.

"That's right, the situation is so dire that it caused me -- a lazy, self-involved, generally self-medicated man child -- to start an entire charity organization," he quipped. "It was through this that we felt we weren't just complaining there was nothing to be done but actively taking steps to do something. Instead of being disappointed that young people were so misinformed about the reality of the disease, we started to educate them."

Rogen was joined by National Institutes of Health Director Francis Collins as well as National Institute of Aging Director Richard Hodes. He even got a few laughs from Committee Chairman Tom Harkin (D-Iowa), who humorously unmasked himself as "House of Cards" star Kevin Spacey and indicated that it was the first time the record has ever used the term "Knocked Up."

"Americans whisper the word Alzheimer's because their government whispers the word Alzheimer's," Rogen said. "And although a whisper is better than the silence that the Alzheimer's community has been facing for decades, it's still not enough. It needs to be yelled and screamed to the point that it finally gets the attention and the funding that it deserves and needs."

Though the actor took to Twitter to share his testimony, he also seemed disappointed about the turnout.

"Not sure why only two senators were at the hearing. Very symbolic of how the Government views Alzheimer's. Seems to be a low priority," he tweeted.

Rogen also called out Sen. Mark Kirk for leaving before he testified, after the Illinois Republican tweeted about the actor's appearance.

".@SenatorKirk pleasure meeting you," he wrote. "Why did you leave before my speech? Just curious."

"All those empty seats are senators who are not prioritizing Alzheimer's," Rogen continued. "Unless more noise is made, it won't change."

The actor reportedly called out senators who left early or dozed off during his comments in an appearance on "Hardball" that will air Wednesday night.